Astronomers may have found giant alien 'megastructures' orbiting a star in the Milky Way

[YNM]

4 hours ago, radonek said:

Can somebody explain to me why it could not be two stars with same spectra occluding each other?

1. One of the star have to be smaller and dimmer, so either the lines won't match in depth (different type ex. MS vs WD, Giant vs MS) or something on that line will occur (different temperature, different color).

2. Even if it was a white dwarf, double lines will be observed due to the redshifts and blueshifts.

Hence why I'm asking whether anyone have really looked up the spectrum. I feel it's impossible not to pinpoint the cause just from that; it's soo precise that you can even tell starquakes off it.

Also, finding everything to detail around the star could help.

Edited May 26, 2017 by YNM

[kerbiloid]

If a neutron star were hit and teared apart, what would be its smaller remnants?
(As bigger ones would probably collapse into a black hole.)

Can't this be pulsar scraps?

Edited May 26, 2017 by kerbiloid

[SinBad]

neutron stars involed in collisions would likely cause a gamma ray burst. as we are here to look at the debris, I reckon it wasn't a neutron star.

[magnemoe]

Add that anything large would generate wobble. 
Looking for wobble on tabbys star should have an high priority. 

[Streetwind]

Here's your chance to get your questions answered straight from the experts.

 

[kerbiloid]

8 hours ago, SinBad said:

neutron stars involed in collisions would likely cause a gamma ray burst. as we are here to look at the debris

If the burst was long ago, while clots of barion matter are grievously orbiting a close star?

[Streetwind]

From the Q&A, it looks like they got all necessary observation done!

Key quotes:
- " We were able to observe in practically every part of the electromagnetic spectrum. "
- " We have Doppler data "
- " Too early to say much. But the observations DO eliminate the idea that there was any artifact in Kepler data. "
- " Expect a short paper on discovery within the month. Will take longer for more detailed work. "

[YNM]

14 hours ago, kerbiloid said:

If a neutron star were hit and teared apart, what would be its smaller remnants?
(As bigger ones would probably collapse into a black hole.)

Can't this be pulsar scraps?

1. Neutron star collision is unlikely to cause debris as in planetary collision. These "star"s are made of degenerate matter - unnormal state of matter that packs WAAY too close - that can only exist under the immense gravitational pressure much, much larger than those found inside a star's core (a few magnitudes or something. big numbers are non-grasp-able.) . If they ever create debris, those debris are going to revert back to non-degenerate state, causing a lot of radiation and (volumetric) matter. We should've seen it.

2. The resulting object post-collision should still be detectable. Radio telescopes or γ-ray or x-ray.

--------

Hmm... "all EM spectrum observable"... is that only photometrically or also spectrometrically ? I think they need the later.

Edited May 26, 2017 by YNM

[Green Baron]

It's been a while but apparently someone is still working on it.

https://arxiv.org/abs/1708.04600

tldr: the hypothesis introduces ringed planets as sources for the anomalous light curves.

 

[Green Baron]

A new explanation, by the original describers:

http://iopscience.iop.org/article/10.3847/1538-4357/aa899c/meta;jsessionid=F8E69D428486198F83420B1D05CB682E.ip-10-40-2-120

tl:dr: dust,

Dimming across the whole star's spectrum does not support the idea of solid objects. But doesn't explain all dimming.

 

Edited October 8, 2017 by Green Baron

[Scotius]

Whatever it its, must be pretty unique. We're watching thousands of variable stars in range of our instruments, but Tabby's still remain a solitary example.

[Green Baron]

Not sure about that, there is a class of irregularly dimming stars. I mean besides the typical periodic variables.

Otoh, it's not that long that we started to watch the surrounding with sophisticated telescopes, like 10-20 years at the most, some have just received instrument-upgrades and adaptive optics (like the GranTeCan, VLT in 2013). I wouldn't be surprised if the number of open questions will keep on growing faster then the number of possible answers. The way it should be, no :-) ?

Edited October 8, 2017 by Green Baron

[insert_name]

Looks like the dust hypothesis has been confirmed

https://gizmodo.com/new-results-quash-alien-megastructure-theory-of-myste-1821734317

[HebaruSan]

57 minutes ago, insert_name said:

Looks like the dust hypothesis has been confirmed

https://gizmodo.com/new-results-quash-alien-megastructure-theory-of-myste-1821734317

To sum up for anyone curious, the article essentially says, "The Las Cumbres observations show that the occulting material, whatever is blocking the star light, preferentially absorbs blue light", which means it's not an opaque structure. There's also no noticeable infrared emission, as would result if such a structure was heated by a star.

[kerbiloid]

We still can hope.

Spoiler

Nanites. They can orbit.

Spoiler

...or Mantrid's standard working arms of Cluster

 

[Green Baron]

"Tabby keeps on dipping, dipping ..." humdidum

Evaluation of photometric data gained by the Las Cumbres network.

https://arxiv.org/abs/1801.00732

tl:dr: either dust or processes in the stars photosphere.

Next dipping season 2019 ?

 

I find the latter interesting, as it is in line with the speculations about the other dipping stars. Or, in general words, processes in the energy budgets of the stars that we do not yet fully understand. Who would have thought ? :-)

Edited February 3, 2018 by Green Baron

[Scotius]

Processes in the star's atmosphere? What could affect such a big area without the star literally ripping itself apart? Or at least becoming noticeably unstable in terms or emitted energy, star wind and changes in the spectrum. I'm not an astrophysicist by any means, but to me it strongly points out to something external.

[Green Baron]

Most dips were between 1 and 2.5%.

Temperature changes are mentioned in the paper. Proposals from other papers include state changes like changes in the convection patterns or stellar radius. Possibilities are enough i'd think but i am only consuming the publications ...

Edited February 3, 2018 by Green Baron

[YNM]

On 04/01/2018 at 12:38 AM, HebaruSan said:

"The Las Cumbres observations show that the occulting material, whatever is blocking the star light, preferentially absorbs blue light"

Guess what they can be...

Spoiler

Good to know it's not an alien death battleforce.